1. Field of the Invention
This invention relates to new and improved pneumatic wand apparatus and method which are particularly adapted for hand-held use in the essentially automatic filling with ambient air of non-elastic dunnage bags to predetermined overpressures in situ in cargo containers.
2. Description of the Prior Art
Although prior art apparatus and methods are known for the filling of dunnage bags with ambient air, none are known which are configured and operable in the manner of those disclosed herein in accordance with the teaching of this invention, in particular with regard to the filling of dunnage bags to predetermined overpressures in situ in cargo containers.
More specifically, and considering first the Dunnage Bag Inflation Air Gun as disclosed in U.S. Pat. No. 4,146,070 to Angarola et al, the same will immediately be seen by those skilled in this art to take the form of a somewhat complex air injection device requiring a plurality of high pressure air fill orifices, and to be strictly limited in operation to use with dunnage bags which include a gun-compatible, highly specialized fill valve assembly, including a separately attachable fill valve assembly sealing member, the overall cost of which would most probably, as a practical cost matter, clearly rule out use of the Angarola air gun with contemporary dunnage bags, which are now being used in vastly increased quantities since the 1979 issue date of the Angarola patent, and which do not as a matter of economic practicality include such highly specialized and costly fill valve assemblies. The Angarola et al inflation gun operates through the entrainment of ambient air by high pressure air jets from the pressurized air fill orifices to force air through the fill valve assembly into the dunnage bag; and, upon filling of the dunnage bag to the specified maximum pressure level, simply dumps excess pressurized air back into the surrounding atmosphere, thus requiring reliance upon the skill and attention of the fill gun operator to detect this condition (see for example telltales 597 in Angarola's FIG. 21), discontinue pressurized air flow to the gun, remove the same from the dunnage bag fill valve assembly, and seal the same; it being noted that although Angarola et al do mention at lines 63-68 of patent specification column 9 that an automatic valve closure member could be employed to close the specialized dunnage bag fill valve upon sensing of a predetermined pressure in the dunnage bag, no specific disclosure of this feature is found in the patent. Under these circumstances, it should be immediately clear that the application of the Angarola et al air gun to the inflation of dunnage bags in situ in cargo containers would most probably be far less than practical, with the high pressure air being dumped from the gun upon bag filling quite possibly damaging or contaminating with dust sensitive cargo of the nature requiring dunnage bag protection, for example sophisticated electronic components or the like, and possibly presenting a safety hazard to the gun operator in violation of contemporary OSHA standards. In addition, the apparent need for precise alignment between the Angarola et al inflation gun and the specialized dunnage bag valve assembly would most probably render such task even more difficult in the somewhat cramped confines of a cargo container.
Referring next to the highly complex, and presumably inordinately expensive Ball Inflation Apparatus as disclosed in U.S. Pat. No. 4,714,098 to Stuckel, the same will immediately be seen to be directed to the inflation of elastic, rather than inelastic, objects, in particular vehicle tires, basketballs and footballs, although cushioning bags are also mentioned; with such elastic objects in any event of necessity comprising self-contained, specialized inflation valve assemblies which require a very small diameter, sharply pointed needle for insertion thereinto to inflate the object. To this effect, Stuckel includes a very small diameter, sharply pointed lubricated coaxial needle assembly which is operationally compatible with such inflation valve assemblies. In Stuckel, an external pneumatic pressure regulator is required to establish a set point for the pressure sensing function; while this prior art inflation apparatus further requires a total in all of at least seven pressure regulators and included gauges, a plurality of valves and connecting lines, and the like, a separate needle assembly lubrication system which includes a lubricating oil reservoir and needle lubrication line, and an output pressure reservoir tank; all to result as above in a highly complex, expensive, and clearly maintenance-prone device. In addition, and unlike the apparatus and method of the subject invention which function to fill non-elastic dunnage bags by essentially and simply sensing the fullness thereof, which is totally satisfactory to the purpose of the dunnage bag, the Stuckel Ball Inflation Apparatus functions to inflate elastic objects to a pre-set pressure and, as such and in accordance with the technological complexity thereof as above, would most probably represent technological overkill, so to speak, if attempts were made to apply the same to the task of this invention. Further, the operational necessity in Stuckel that the object to be inflated include the types of specialized fill valve assemblies commonly found in footballs, basketballs and vehicle tires would most probably, ab initio, disqualify the Stuckel apparatus for the filling of contemporary dunnage bags for the simple but obvious reason that the same, for cost considerations, do not include these types of specialized fill valve assemblies. In addition, it is not seen how the Stuckel Ball Inflation Apparatus could, in any event, as a practical matter be satisfactorily applied to the filling of dunnage bags in situ in a cargo container since some portion of the lubricating oil supplied to the coaxial inflation needle assembly would, as a virtual certainty, rub or be blown off the same with resultant contamination of the container cargo; while the sharpness of that needle assembly in the relatively cramped confines of a cargo container could very well result in the puncture of the dunnage bag by the same. Too, and to the extent made clear by the Stuckel disclosure, the Ball Inflation Apparatus thereof would by no means appear suitable to hand-held use within the confines of a cargo container. There is, in any event, no disclosure in Stuckel of the sensing of an abrupt change in the fluidic effect of the flow of the inflation air through the generation and use of negative pressure by a venturi at the tip of the Stuckel coaxial needle to sense the fullness of the object being inflated in accordance with the teachings of the subject invention; which teachings would not be technically relevant or operable in Stuckel wherein the pressure in the object being inflated is sensed through an orifice in the side of the coaxial needle without regard for the fluidic effect of inflation air flow at the needle tip, and wherein elastic objects are being inflated to a pre-set and quite substantial overpressure, for example 50 PSIG as would not be uncommon with certain types of vehicle tires, but would of course, immediately burst contemporary dunnage bags.
Referring next to the Automatic Nozzle disclosed in U.S. Pat. No. 3,327,740 to Murray, and the Automatic Dispensing Nozzle disclosed in U.S. Pat. No. 3,312,257 to Knapp II, et al, these devices will immediately be seen to be limited to the automatic shut-off of the flow of gasoline to the gasoline tank of a motor vehicle in what has now become essentially conventional manner upon filling of the tank. Thus, and although this automatic shut-off of gasoline flow is accomplished in each instance by the sensing of the loss of an active vacuum signal generated by gasoline flow through the fill nozzle when the gasoline level blocks a venturi port, the same would clearly have absolutely no applicability to the filling of dunnage bags with air. In addition, there is, in any evnet, no provision for adjustability in these gasoline fill nozzles, in particular since gasoline is, of course, substantially incompressible; while the venturi effect in each of the same is created internally of the generally complex nozzle body assemblies rather than at the nozzle discharge tube.
Considering next the Pneumatic Amplifiers disclosed in U.S. Pat. No. 3,794,058 to Riley, and the Pneumatically Amplified Conservation Valve disclosed In U.S. Pat. No. 4,575,042 to Grimland et al, it will be immediately clear that although each of these devices does illustrate the by now generally well known concept of employing a pneumatic amplifier to generate an output signal to control a valve in response to the sensing of an externally generated input signal, there is nothing in either of these patent disclosures, which are respectively directed to the fluidic amplifier control of a proportional fluid valve and an oxygen conservation valve, to in any way suggest the application of the principles thereof to the control of filling of non-elastic dunnage bags with ambient air.
Considering lastly the Pressure Regulators disclosed in U.S. Pat. No. 3,805,823 to Kakegawa which illustrate pilot operated pressure regulators with a modulated main diaphragm to increase the accuracy of secondary pressure settings, with applications to both gas and liquid pressure regulation, it is clear that the same are of general interest only with regard to the subject matter here at hand in having no relevance or applicability to the filling of dunnage bags with ambient air.